Molecular cloning, tissue distribution and ontogenetic regulation of sodium/proton exchanger isoform 2 (NHE-2) mRNA expression were evaluated in the pig small intestine during postnatal development. The 2872-bp porcine full cDNA sequence of the NHE-2 (EF672046) cloned in this study showed 80% and 70% homology with known human and mouse gene sequence, respectively. Hydrophobic prediction suggests 13 putative membrane-spanning domains within porcine NHE-2. The porcine NHE-2 mRNA was detected in the brain, liver, kidney, heart, lung, small intestine and muscle. The small intestine had the highest NHE-2 mRNA abundance and the brain, lung and liver had the lowest NHE-2 mRNA abundance (P < 0.05). Along the longitudinal axis, the duodenum had the highest NHE-2 mRNA abundance and the ileum and colon had the lowest NHE-2 mRNA abundance (P < 0.05). The NHE-2 mRNA level was increased from day 1 to day 26 in the duodenum (P < 0.05) and dropped dramatically on day 30 (P < 0.05). There is no difference between day 1 and day 7 (P > 0.05). After day 30, the NHE-2 mRNA level remained the same except on day 90 (P > 0.05). The mRNA expression of NHE-2 was not only differentially regulated by age but also differentially distributed along the small intestine of piglets at early stages and growing stages of life, which may contribute to changes in NHE activity.

When comparing progeny-testing schemes with individual performance selection, one should use equivalent selection intensities and population structures in the two systems. Adapting formulae from open-nucleus theory, the relative efficiency of progeny testing has been tested for a range of heritabilities, fertility levels, upward gene-transfer rates, mating ratios and numbers of sires selected. In sheep and beef cattle breeding, the heritability of the trait under consideration has usually to be very low to make progeny testing worth-while. High fertility increases genetic gains but does not change the relative efficiency of progeny testing. Opening the nucleus to females from the base increases genetic gains and reduces relative efficiency of progeny testing, both effects being of small magnitude. For fixed mating ratios, only a small fraction of females should be in the nucleus, but for fixed sire numbers approximately one-third of the population should be mated to proven sires. In these analyses, variances were adjusted for the effects of repeated selection and for the effects due to mixing groups with different means. This adjustment did reduce absolute genetic gains, but did not change conclusions on progeny testing efficiency and optimum design.

Two separate experiments were conducted to evaluate the effect of betaGRO® supplementation on in vitro porcine fetal myoblasts (PFM) and porcine satellite cells (PSC) proliferation, fusion and myotube thickness. The PFM and PSC were isolated from the m. longissimus dorsi of day 60 of gestation fetuses and piglets within 24 h of birth, respectively. Proliferation assays were conducted as 4×3 factorial arrangements with time of culture (24, 48, 72, 96 h) and media treatment (standard porcine media supplemented with 10% (vol/vol) fetal bovine serum (HS); HS without 10% fetal bovine serum (LS); and LS supplemented with 10 mg/ml betaGRO® (BG)) as main effects. Fusion and myotube growth assays were conducted as 2×2 factorial designs with serum concentration (HS or LS), and betaGRO® inclusion (0 or 10 mg/ml) as main effects. There was a treatment×time interaction and betaGRO®×serum interactions for proliferation, fusion and myotube thickness of PFM (P<0.01). At all-time points, HS and BG-PFM had greater proliferation rates compared LS (P<0.01). The HS treatment had greater proliferation rates than BG (P<0.02) except at 72 h of culture (P=0.44). When betaGRO® was added to LS media, fusion percentage and myotube thickness decreased (P<0.01), while fusion percentage increased (P<0.01) and myotube thickness was unaffected (P=0.63) when betaGRO® was added to HS media. There were treatment×time and betaGRO®×serum interactions for proliferation rate and fusion rate of PSC, respectively (P<0.01). At all-time points, HS had greater proliferation rates than LS and BG (P<0.01), and LS had greater proliferation rates than BG (P<0.02). When betaGRO® was added to LS and HS media, fusion percentage increased for both media types (P<0.01). There was no betaGRO®×serum interaction (P=0.63) for PSC myotube thickness; however, betaGRO® supplemented myotubes were thicker (P<0.01) than non-betaGRO® supplemented myotubes. These two experiments indicate in vitro betaGRO® supplementation stimulates divergent responses based on the age of cell examined.

The length of the oestrous cycle observed in 20 ewe lambs and 424 ewes of the Awassi breed gave mean values of 16·4 (s.d. 1·31) days for ewe lambs and 17·4 (s.d. 1·84) days for ewes. Plane of nutrition did not affect cycle length in ewe lambs and age of ewe (from 2 to 5 years) did not affect oestrous cycle length in ewes (P > 0·05). Of 40 ewes treated with progesterone intravaginal sponges 33 (83%) showed oestrus and 28 (70%) ovulated at the first (synchronized) and 31 (78%) and 30 (75%) at the repeat oestrus. Mean duration of oestrus was 40·0 (s.d. 16·37) h (range 8 to 72) for the first and 34·7 (s.d. 11·19) h (range 16 to 54) for the repeat oestrus. Ovulation rate, measured in the same ewes, gave mean values of 1·18 (s.d. 0·460) for the first and 1·223 (s.d. 0·440) for the repeat oestrus.

Most commercially available silage inoculants are supplied as freeze-dried preparations of lactic acid bacteria (LAB) which are rehydrated immediately prior to application to herbage (Wilkinson, 1989). One limitation of this approach is that rehydrated bacteria are likely to be less active initially than ‘freshly cultured’ (actively growing) cells. Thus an extended lag phase may precede the period of logarithmic growth of freeze-dried inoculants. From the above argument, it follows that freshly cultured bacteria may be preferable in order to enhance activity in the initial period of ensilage.

In two experiments, firstly the principle of using freshly cultured inoculants was examined in laboratory silos followed by a scale-up of the inoculant production process to investigate the practicability of using it in an on-farm system, and examining its effect on silage composition and cattle production response.

The effect of bromocryptine on milk production was investigated in 32 crossbred ewes (Flemish Milksheep х Suffolk) with one sucking lamb, during lactation and during drying off. After weaning the lambs, all ewes were hand milked twice daily for 3 days. From day 4 onwards, the ewes were divided into four groups with equal mean daily milk production. Ewes of groups A and B were hand milked twice daily during the following 9 days. Ewes of groups C and D were dried off by reducing the milking frequency. They were milked on days 5, 8 and 12. In groups B and D, bromocryptin (1 ml of 1 g/l ethanol 50%) was injected intramuscularly twice daily while control ewes (groups A and C) received 1 ml ethanol 50%. Blood samples were taken by venipuncture prior to each injection and were assayed for prolactin, growth hormone, thyrotropin and cortisol.

Bromocryptine decreased plasma prolactin levels but did not alter growth hormone or cortisol concentrations during lactation or drying off. Thyrotropin levels were elevated by bromocryptine during drying off but were unaffected during galactopoiesis.

During lactation the daily milk production remained unchanged in control ewes while in bromocryptine-treated ewes a proportional decrease of 0·5 was observed. In all ewes the decrease in milk production occurring at drying off could not be accelerated or stimulated by bromocryptine.

It is concluded that prolactin plays an important role in galactopoiesis in ewes but its role is comparatively unimportant compared with other factors during mammary involution.

Two experiments were conducted to examine the effects of dietary inclusion of an ephedrine (Eph)/caffeine (Caf) mixture on finishing (55 to 100 kg live weight) castrated male pigs. The first experiment was conducted as a dose-response study and showed that the mixture had an optimal effect on performance and carcass composition at a dietary inclusion level of approximately 56/560 mg/kg of Eph and Caf, respectively. In the second experiment, interactions between the compounds were studied by dietary inclusion of Eph (56 mg/kg) and Caf (560 mg/kg) separately or as a mixture (56/560 mg/kg). The mixture reduced food intake by 0·12 and improved the food: gain ratio by 0·08. Muscle protein deposition rate was increased proportionately by 0·25, lipid accretion rate was decreased proportionately by 0·27, and gross energetic efficiency of energy deposition decreased proportionately by 0·09. This resulted in a changed proportional carcass composition towards more muscle (0·08) and less fat (0·21) after treatment with the mixture. The reduction in food intake was sustained due to an interaction over the first 3 weeks of treatment changing to additive effects by the compounds. The increased muscle protein deposition rate after feeding the mixture was entirely due to Eph, while the decreased gross energetic efficiency of energy deposition was caused by Caf. On the other hand, both compounds contributed almost equally to the decrease in lipid accretion rate. These results show that an Eph/Caf mixture markedly improves performance and body composition in finishing castrated pigs.

Changes in prices of the basic cereals make it necessary to have a reliable assessment of their relative nutritive values if maximum economic efficiency of pig production is to be attained. As the primary role of cereals in pig feeds is as a source of energy, it is on this basis that comparison should be made but with due allowance for any major differences in nutrient content which may necessitate differential supplementation.

Sorghum, or milo, is a cereal imported into the United Kingdom which, at times, may be competitive with other cereals for price per ton but about whose nutritive value there is some confusion. Sorghum has not often been compared with barley as a cereal for pigs, but its value relative to that of maize seems to vary widely, between 80 and 100% (Braude, Mitchell and Robinson, 1950; Hillier, MacVicar and Pond, 1954; Aubel, 1956; Loeffel, 1957; Peo and Hudman, 1958; Schruben, 1959; Vanschoubroek, Spaendonk and Nauwynck, 1964). Estimates of relative digestible energy values (DE) are equally variable; the DE value of sorghum has been assessed as 94·5% (Diggs, Becker, Terrill and Jensen, 1959) and 96·2% (Robinson and Lewis, 1962) that of maize, whereas the TDN value given by Evans (1960) is greater than that of maize. Robinson and Lewis (1962) consider the DE value of sorghum to be 140% ofthat of barley, but Evans (1960) quotes a TDN value for sorghum which is 111% of that of barley. While variation in the type of sorghum used may account for some of this discrepancy, Dammers and Djikstra (1961) found little difference between the varieties milocorn, kaffir corn, granifero and white dari, and only guinea corn differed in having a lower energy value.

Two rations were prepared for sheep in which whole oat grain was mixed with molasses, urea, minerals and vitamins. Chemical analysis showed that the minerals had adhered to the grain and that there was little loss of minerals after one year of storage. The diets were readily consumed by sheep.

Twelve inbred (coefficient of inbreeding 25%) and 12 outbred, singlereared, Scottish Blackface castrated male lambs were taken at six months of age from amongst the progeny of three rams. They were housed and fed individually on a pelleted diet in three separate phases. In the first two phases restricted amounts were offered. These were calculated to produce, firstly, a small rate of live-weight gain and, secondly, a small rate of live-weight loss. In the third phase feed was offered to maximum voluntary intake during 2 two-hour periods daily.

On restricted intakes there were no significant differences between the groups. In the third phase the outbred sheep consumed 17% more feed than the inbred group and the daily rates of live-weight gain and wool growth were 33% and 27% higher, respectively. Since the inbred lambs were smaller, the voluntary intake per unit live-weight did not differ significantly between groups.

The estimated requirements of feed for maintenance (20·1 ± 0·4 and 21·9±0·6 g./kg. live-weight, respectively, for the outbred and inbred groups) differed significantly. There were no apparent differences in the estimated efficiency of conversion of available surplus feed to body tissue or wool growth.

The consumption of grass silage by each individual cow in a group housed during two consecutive winter-feeding periods was continuously recorded. During the first winter, one of two concentrates, containing high starch or high fibre, were offered on a sliding scale and half the cows were injected with bovine somatotropin (bST). During the second winter, one of two concentrates, containing high or low rumen-undegradable protein were offered at a flat rate ivith two-thirds of the cows receiving bST. The cows injected with bST had significantly greater yields of milk but their consumption of silage was similar to that of cows not treated with bST. The type of concentrate offered had no significant effect on silage consumption. Although there were significant variations in the consumption of silage from day to day, there were highly significant variations in consumption attributable to individual cows. This individuality of intake persisted in a consistent manner throughout a feeding period and could not be explained on the basis of milk production, body weight, age or parity. In 24 of the cows which were used in both years, their individual intakes for the two periods were significantly correlated. The possibility that this individuality may be of economic importance is discussed.

The plasma concentrations of glucose, insulin, lactate, cortisol and free fatty acids were investigated in normal pigs and those with the homozygous and heterozygous genetic mutation for malignant hyperthermia (MH). Blood samples were obtained during a 24-h resting period, a glucose tolerance test and during a treadmill test with submaximal physical load conditions. The homozygous MH positive animals elicited the highest glucose concentrations and the homozygous MH negative animals the lowest at each sampling time during the 24-h period (P < 0·01). During the glucose tolerance test, the most pronounced post-prandial increase and the highest plasma concentrations of glucose were found for the homozygous MH positive animals (P < 0·01), which was associated with a late release of insulin. Increasing work loads during the treadmill test run resulted in an increase of plasma cortisol concentrations in all animals (P < 0·01), with the more pronounced increase for the homozygous and heterozygous MH positive animals. Plasma free fatty acid concentrations during the treadmill test differed between the genotypes (P < 0·05). A pronounced increase was found for the homozygous and heterozygous MH positive animals, whereas the MH negative animals provided very constant free fatty acid values, at a low level, independent of the work load. These results indicate that the genetic mutation for MH in pigs affects the metabolic pathways of the energy metabolism, resulting in higher plasma glucose concentrations at rest and higher lipolytic activities under physical load conditions.

Two Pietrain/Hampshire crossbred males and two Large White males were mated in equal numbers to 24 Large White females. Breed of sire did not affect litter size or total weight at birth or weaning. After weaning, on ad libitum feeding over the live-weight range 25 to 88 kg, the crossbred pigs grew more slowly to slaughter (5%) but with equal efficiency of live-weight gain. Crossbreds had higher carcass yields (3%) shorter carcasses (3%) and larger ‘eye-muscle’ areas (18%). Fat depths, joint proportions and cut-out values were not affected. The ‘eye-muscles’ of crossbreds were paler in colour and had a lower water-binding capacity than those of the purebreds, but pH1 values and transmission percentages did not differ.

1. Four growth trials were carried out with 297 group-fed steers given diets based on barley, minerals and vitamins, unsupplemented or supplemented with either soya bean meal or various sources of non-protein nitrogen.

2. Steers given unsupplemented barley (11% crude protein in dry matter) had inferior growth rates up to 300 kg live weight but thereafter were equal to those given barley supplemented with urea in the drinking water or soya bean meal.

3. There were no significant differences in the growth rates of steers given barley supplemented with soya bean meal and those given barley supplemented with ammonium and mineral salts of formic acid or a mixture of acids (predominantly acetic).

4. In two out of three trials, tenth-rib joints from steers given barley supplemented with ammonium salts of mixed acids contained less fat and more protein and water than those from steers given barley supplemented with soya bean meal or proprietary protein supplements.

5. A number of possible explanations for the apparent carcass differences is discussed.

Previous work has shown that a sward height of 3-5 cm for sheep is the most efficient way of maintaining a balance between new .growth and decayed material. An unreplicated experiment was carrried out during 1985 using 77 cross-bred ewes and their Suffolk x twin lambs to graze a perennial ryegrass sward (Lolium perenne) cv Wendy between 29 April and 22 July (weaning). Animal performance was monitored and grazing behaviour noted. Sward height measurments were taken twice weekly with an HFRO sward stick on a 0.4 ha plot (P) and on the remaining 5.8 ha field (F). Grazing commenced on each area when the sward height reached 4 cm ± 1 and was maintained at this height on P by adjusting animal numbers. Physical data was recorded from a minimum core flock of 5 ewes and 10 lambs. Area F was set stocked at 12.4 ewes/ha. Areas F and P received 198 kg N/ha in total, applied at monthly intervals between early April and July. Net herbage accumulation was recorded at 21 day intervals under exclusion cages on each area.

The effects of an established Trichostrongylus colubriformis infection on amino acid (AA) absorption from the small intestine and their availability to other tissues were determined in lambs 48 days post infection. The lambs were fed fresh Lucerne (Medicago sativa; ∼800 g dry matter (DM)/day) and dosed with 6000 L3 T. colubriformis larvae for 6 days (n = 5) or kept as parasite free controls (n = 6). Faecal egg production was monitored every second day from day 22 to day 48. A nitrogen (N) balance was conducted on days 35 to 43 after infection, and digesta flow and AA concentration measurements were made on day 44. On day 48 after infection, blood was continuously collected from the mesenteric artery and vein, plasma harvested and AA concentrations measured. Faecal egg production peaked on the 26th day after infection (P < 0.001) and intestinal worm burdens on day 48 were greater (P < 0.001) in the infected lambs. Feed intake and liveweight gain were similar (P > 0.10) between control and infected lambs. Digestibility and flow of DM and N through the digestive tract were also unaffected (P > 0.10) by parasite infection. Despite a trend towards higher abomasal AA flux in the parasitised lambs (P < 0.10), apparent AA absorption from the small intestine and AA availability to other tissues were unaffected (P > 0.10) by infection. These results suggest that an established parasite infection had little effect on the intestinal absorption and availability of AA to other tissues in lambs fed fresh Lucerne.

Fourteen growing Belgian White Blue bulls were assigned to three groups: five controls (C); five bulls implanted with 140 mg trenbolone acetate and 36 mg Zeranol (TBA-Z); and four bulls implanted with 140 mg trenbolone acetate and 20 mg oestradiol-17β (TBA-E2). Testosterone (T) and luteinizing hormone (LH) levels in blood plasma were determined at day 0, 30 and 60. Mean plasma LH concentrations measured by repeated sampling over a 10-h period were similar at day 0, 30 and 60 in the three groups. At days 30 and 60, T levels were significantly lowered in treated bulls: namely 2·0 (s.d. 0·7) μg/1 v. 2·7 (s.d. 0·5) μg/1; 0·7 (s.d. 0·1) μg/1 v. 1·0 (s.d. 0·3) μg/1; 0·5 (s.d. 0·1) μg/l v. 0·4 (s.d. 0·2) μg/1 in the C, TBA-Z and TBA-E2 groups respectively. Moreover, anabolic compounds completely abolished pulsatile liberation of LH and T.

In control bulls intravenous injection of 0·5 ng/kg body weight of LH releasing hormone (LHRH) caused the release of a large quantity of LH (10 to 13 times the basal level after 10 min) followed by an increase in plasma T levels. On the other hand, LH and T responses to LHRH were reduced by TBA-E2 and TBA-Z treatments. A delay in LH response to LHRH was apparent 6 days after anabolic treatment. However, the total amount of LH liberated during the test was increased. The second effect was a quantitative reduction at days 20, 30 and 60 in LH and T secretion after LHRH. The modification of the hormonal pattern was quicker and more pronounced in TBA-E2 than in TBA-Z animals. Correlation was negative (r = −0·68; P < 0·05) between the mean daily gain during the experimental period and the total quantity of T liberated by the testis after LHRH stimulation at day 60. It was concluded that administration of trenbolone acetate plus Zeranol or trenbolone acetate plus oestradiol-17β in pubertal bulls reduced the LH and T responses to LHRH and abolished the pulsatile LH and T secretions.

Few people question the basis of their moral viewpoints, yet if science is to be applied ethically it is necessary to subject these viewpoints to rational analysis. The paper provides an overview of prominent ethical theories (deontological and consequentalist) and their impact on novel and prospective animal biotechnologies. These theories are applied to the principles of: autonomy, justice, nonmaleficence and beneficence in relation to the interests of animals, the environment and humans.

Deontological approaches include ‘rights’-based theories (often derived intuitively or from scriptural sources) and ‘contractualist’ theories, dependent on an ‘unwritten contract’ between rational beings to ensure fairness. For consequentialists (eg utilitarians), it is the outcome of actions that determines their ethical value. Few people, consciously or unconsciously, consistently employ a single ethical theory, but there is often much concordance between actions based on the different theories. Except for some intuitionists, ethicists emphasise the role of rationality in ethical theory; for even though intuition is an important element, many consider that universalizability of ethical theories entails the establishment of a ‘reflective equilibrium’

Circular data originates in a wide range of scientific fields and can be analyzed on the basis of directional statistics and special distributions wrapped around the circumference. However, both propensity to transform non-linear to linear data and complexity of directional statistics limited the generalization of the circular paradigm in the animal breeding framework, among others. Here, we generalized a circular mixed (CM) model within the context of Bayesian inference. Three different parametrizations with different hierarchical structures were developed on basis of the von Mises distribution; moreover, both goodness of fit and predictive ability from each parametrization were compared through the analyses of 110 116 lambing distribution records collected from Ripollesa sheep herds between 1976 and 2017. The naive circular (NC) model only accounted for population mean and homogeneous circular variance, and reached the lowest goodness-of-fit and predictive ability. The CM model assumed a hierarchical structure for the population mean by accounting for systematic (ewe age and lambing interval) and permanent environmental sources of variation (flock-year-season and ewe). This improved goodness of fit by reducing both the deviance information criterion (DIC; −2520 units) and the mean square error (MSE; −12.4%) between simulated and predicted lambing data when compared against the NC model. Finally, the last parametrization expanded CM model by also assuming a hierarchical structure with systematic and permanent environmental factors for the variance parameter of the von Mises distribution (i.e. circular canalization (CC) model). This last model reached the best goodness of fit to lambing distribution data with a DIC estimate 5425 units lower than the one for NC model (MSE reduced 13.2%). The same pattern revealed when models were compared in terms of predictive ability. The superiority revealed by CC model emphasized the relevance of heteroskedasticity for the analysis of lambing distribution in the Ripollesa breed, and suggested potential applications for the sheep industry, even genetic selection for canalization. The development of CM models on the basis of the von Mises distribution has allowed to integrate flexible hierarchical structures accounting for different sources of variation and affecting both mean and dispersion terms. This must be viewed as a useful statistical tool with multiple applications in a wide range of research fields, as well as the livestock industry. The next mandatory step should be the inclusion of genetic terms in the hierarchical structure of the models in order to evaluate their potential contribution to current selection programs.

Twenty-eight Landrace × (Landrace × Large White) young female pigs (gilts) were allocated to one of four treatment groups at about 75 kg live weight. The gilts were mated at second oestrus and suckled their piglets for 35 days. Gilts were slaughtered 14, 21, 28 or 35 days after weaning. The ‘effective’ food conversion ratios (i.e. total gilt plus litter feed intake (kg) divided by total gilt weight gain plus litter weaning weight) of the four groups were 5·22; 4·70; 4·62; and 4·56 respectively. The differences were not statistically significant.

Neither carcass weights nor individual joint weights were significantly affected by treatment. Samples of 11 middle sections from the 14-, 21- and 28-day slaughter groups were boned and cured. Bacon produced from the streak blocks had poor colour, texture and moisture-holding capacity. It was concluded that streak blocks from gilts that had farrowed were unsuitable for curing as streaky bacon.